This started when I got a load of 775 and 771 Xeon CPU's for cheap, on average they cost me £3 each.
So I got a few old 775 mobo's, some cheapo GPU's (the one I'm using in this build was won for £10 off ebay as untested but works fine) and some 1GB sticks of DDR2.
I had a zalman cooler and a crappy CiT PSU laying around so used those, got a few 250-320 GB HHD's for dirt cheap.
I put this one together on my home made test bench to see what kind of performance I could get, I used Tomb Raider to test the different GPU's out (6870's and 460's) and they perform great for the money, around 35-55 FPS on a mix of medium and high @1080p.
Really pleased with the price to performance of this ghetto test build, I'm gonna get some cheapo cases and make a few really budget gaming PC's out of it all, but I need to mod some of the Xeons and mobo's as most of them are 771, the x3220 in this one is 775.